Tele-orbs are used in the Fist of Guthixminigame. When the orb is broken, the player is transported to the middle of the playing field; once broken, it cannot be returned unless a new game is started. At the beginning of the game, each player receives one of these, along with 5 bandages, 1,000 elemental runes and 300 catalytic runes.

Also, if you still have it while second round is ending and try to break it when you just have killed your target, game says: "The round is ending, so there is no point in using that now."